Drive belt systems are known. A drive belt system typically comprises a plurality of drive shafts, each drive shaft coupled to a corresponding drive pulley. A motor is arranged to power one drive shaft. This latter drive shaft is known as a motor drive shaft, and the corresponding drive pulley is known as a motor drive pulley. A drive belt couples the motor drive pulley to the remaining drive pulleys. When the motor is energized, the motor drive shaft rotates which, in tum, rotates the motor drive pulley. The motor drive pulley rotation, in tum, moves the drive belt which, in turn, causes is the remaining drive pulleys to rotate.
One known problem with drive belt systems is arcing. Arcing occurs when voltage builds up on the drive belt and on the rotating drive shafts and drive pulleys during operation. Testing has shown that 400-Volt buildups on rotating drive shafts of outer motor rotors are common. Also, testing has also shown that 2500-Volt buildups on the drive belt are common. This is due to the large surface area of the rotating outer hub. When the voltage on the drive belt or on the motor rotor reaches a sufficient level, arcing to ground will occur. This high-voltage arcing results in several problems.
The arcing ground path typically will include the drive shafts, which typically include bearings. This high-voltage arcing in the bearing--called "fluting"--results in bearing surface deterioration.
Also, this high-voltage arcing also causes electromagnetic emission ("EME"). This EME, in turn, results in unwanted noise in the drive belt system's host environment. For example, modern printing machines typically contain a plurality (perhaps 20-30) of individual drive belt systems. If each drive belt system generates EME, the cumulative noise presented to the host printing machine may be substantial.
The problem, therefore, is how to reduce arcing in drive belt systems.
In the past, arcing in drive belt systems has been reduced by grounding substantially all rotating parts in drive belt systems. This grounding typically has been done by using brushes rubbing on all rotating parts. These brushes are carbon fiber and have many strands. The brushes have been mounted to all motors or to their rotating shafts, thus potentially resulting in a large number of total brushes. The cost of each brush and its mounting has been in the $1.50 to $2.00 range. Because of the large number of brush grounds required in a large system, the reliability of the grounding and the system is reduced. Also, the large number of grounding brushes also require more space and increase the system cost significantly.
As a result, there is a need for an improved drive belt system.